Science Requirements: IDDO Electrothermal Drill

The IDPO Science Advisory Board identified in the IDPO Long Range Science Plan 2017-2027 a priority need to repair and upgrade the Electrothermal Drill to allow for coring to 300 m through temperate and polythermal firn and ice. The current IDDO Electrothermal Drill (aka Thermal Drill) melts an annulus around the 3.4 inch diameter ice cores it collects. It can be substituted for the 4-Inch drill sonde or the Badger-Eclipse sonde, for use in ice warmer than about -10 degrees C. Within the next several years, upgrades to the Thermal Drill will allow coring to 300 m through temperate and poly-thermal firn and ice. Water flow rates on the order of 10-4 m3s-1 through firn may be encountered. The system must remain agile and light weight (transportable by helicopter sling load; less than ~400 lb not including fuel), and so use of the Badger-Eclipse drill, rather than the 4-Inch drill, may offer logistical benefits. Applications for the thermal drill include alpine regions and areas of the polar ice sheets where surface melting is significant, and where recently-discovered firn aquifers are undergoing study. For depths shallower than 30 m, a simpler tripod assembly for operation of the drill has been used with good success. The Thermal Drill is particularly useful in ice close to the pressure melting point, where electromechanical drills are at risk from melting and refreezing of the surrounding ice. From discussions organized by IDPO with iterative discussions between IDPO, scientists, and IDDO staff, these are the science requirements for the IDDO Electrothermal Drill.